Decimal to octal number

octal.c

#include<stdio.h>
void main()
{
    int num,i,d1,r1,d2,r2,d3,r3,d4,r4,d5,r5,d6,r6,d7,r7,d8,r8,d9,r9,octal;
    printf("Enter the num ");
    scanf("%d",&num);

     printf("DECIMAL\tOCTAL\n");

    for(i=0;i<=num;i++)
    {

    d1=i/8;
    r1=i%8;

    d2=d1/8;
    r2=d1%8;

    d3=d2/8;
    r3=d2%8;

    d4=d3/8;
    r4=d3%8;

    d5=d4/8;
    r5=d4%8;

    d6=d5/8;
    r6=d5%8;

    d7=d6/8;
    r7=d6%8;

    d8=d7/8;
    r8=d7%8;

    d9=d8/8;
    r9=d8%8;

    octal=(r1*1) + (r2*10) + (r3*100) + (r4*1000) + (r5*10000) + (r6*100000) + (r7*1000000) + (r8*10000000) + (r9*100000000) + (d9*1000000000);

    printf("  %d  \t  %d\n",i,octal);

    }
}

Output:
Enter the num 15
DECIMAL OCTAL
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 10
9 11
10 12
11 13
12 14
13 15
14 16
15 17